I think that the time to replace my PSU is somewhat due. I have been rocking the same PSU in all of my builds since 2007-08 so that's 12 to 13 years of heavy service from a Thermaltake Toughpower 1200w.

I have no real need to replace it. The fan within the unit is still functioning perfectly as it did since new (albeit not active). However, I have noticed that over the last few years my systems never seems to boot as it should at times. For example, I can have the system on full stock and yet the system will boot loop, and the only way to resolve it is to pull the cable and try and clear the capacitors as much as possible.

Since power requirements have changed a lot, I guess I am not getting as much efficiency from this PSU I once did when I was running Quad SLI.

I'd like to go for something that is reliable, has served me as well as this PSU has done so. This PSU with being so old has actually supported everything I have thrown at it within the years. i.e 2x 8 pin motherboard connectors, array of PCI-E power requirements as well.

Not entirely sure on which wattage I'll need, but I think 850 is probably a good bet.

Corsair, Seasonic, Fractal, EVGA, probably a few more in any range from 600-750 watts is more than enough for your system. Just find one in whatever 80 rating you want(like gold, silver, titanium, etc) and fully/semi modular.

I love the fact that the suggestions pretty much half my current wattage capacity. It just goes to show how much technology has changed. This PSU first powered at 45nm CPU. Now we have 7nm CPUs from AMD!

I guess as times goes on more and more hardware will require less wattage

Thanks for the food for thought, I just don't want this PSU popping and taking out the only hardware that I have.